CyberSecBulletin
CVE-2026-23089NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-23089 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 51b1aa6fe7dc87356ba58df06afb9677c9b841ea, 56fb6efd5d04caf6f14994d51ec85393b9a896c6, 7009daeefa945973a530b2f605fe445fc03747af as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 51b1aa6fe7dc87356ba58df06afb9677c9b841ea or 56fb6efd5d04caf6f14994d51ec85393b9a896c6 or 7009daeefa945973a530b2f605fe445fc03747af or 7bff0156d13f0ad9436e5178b979b063d59f572a, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.249 or 5.15.199 or 6.1.162 or 6.6.122, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux6639b6c2367f884ca172b78d69f7da17bfab2e5e up to, but not including, 51b1aa6fe7dc87356ba58df06afb9677c9b841ea; 6639b6c2367f884ca172b78d69f7da17bfab2e5e up to, but not including, 56fb6efd5d04caf6f14994d51ec85393b9a896c6; 6639b6c2367f884ca172b78d69f7da17bfab2e5e up to, but not including, 7009daeefa945973a530b2f605fe445fc03747af; 6639b6c2367f884ca172b78d69f7da17bfab2e5e up to, but not including, 7bff0156d13f0ad9436e5178b979b063d59f572a; 6639b6c2367f884ca172b78d69f7da17bfab2e5e up to, but not including, e6f103a22b08daf5df2f4aa158081840e5910963; 6639b6c2367f884ca172b78d69f7da17bfab2e5e up to, but not including, dc1a5dd80af1ee1f29d8375b12dd7625f6294dad; 6639b6c2367f884ca172b78d69f7da17bfab2e5e up to, but not including, 930e69757b74c3ae083b0c3c7419bfe7f0edc7b2; 2.6.1351b1aa6fe7dc87356ba58df06afb9677c9b841ea, 56fb6efd5d04caf6f14994d51ec85393b9a896c6, 7009daeefa945973a530b2f605fe445fc03747af, 7bff0156d13f0ad9436e5178b979b063d59f572a, e6f103a22b08daf5df2f4aa158081840e5910963, dc1a5dd80af1ee1f29d8375b12dd7625f6294dad
LinuxLinux Kernel2.6.13 up to, but not including, 5.10.249; 5.11 up to, but not including, 5.15.199; 5.16 up to, but not including, 6.1.162; 6.2 up to, but not including, 6.6.122; 6.7 up to, but not including, 6.12.68; 6.13 up to, but not including, 6.18.8; 6.195.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.68, 6.18.8

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix use-after-free in snd_usb_mixer_free() When snd_usb_create_mixer() fails, snd_usb_mixer_free() frees mixer->id_elems but the controls already added to the card still reference the freed memory. Later when snd_card_register() runs, the OSS mixer layer calls their callbacks and hits a use-after-free read. Call trace: get_ctl_value+0x63f/0x820 sound/usb/mixer.c:411 get_min_max_with_quirks.isra.0+0x240/0x1f40 sound/usb/mixer.c:1241 mixer_ctl_feature_info+0x26b/0x490 sound/usb/mixer.c:1381 snd_mixer_oss_build_test+0x174/0x3a0 sound/core/oss/mixer_oss.c:887 ... snd_card_register+0x4ed/0x6d0 sound/core/init.c:923 usb_audio_probe+0x5ef/0x2a90 sound/usb/card.c:1025 Fix by calling snd_ctl_remove() for all mixer controls before freeing id_elems. We save the next pointer first because snd_ctl_remove() frees the current element.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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